The field of this invention relates to the connection together of first and second tubular members for fluid flow therebetween and in particular, to the re-establishment of a connection between severed portions of an underwater pipeline.
The tremendous amount of offshore oil and gas well drilling and production has precipitated more and more underwater pipelines which carry the produced oil and/or gas to storage facilities located either in the water or on the nearest land mass. Typically, these underwater pipelines are comprised of sections of pipe which are interconnected by welding and weight-coated with concrete to insure negative buoyancy so that the pipeline will rest upon the ocean floor. Such pipelines need repair from time to time due to corrosion, failure of welded connections or for other reasons. Typically, in making repairs to an underwater pipeline, it is necessary to remove a damaged section and replace that section with a new, undamaged pipeline section. Such replacement requires underwater welding, which is an extremely time-consuming and technically difficult task. Various coupling devices have been developed to eliminate the need for underwater welding. The problems with making any type of underwater connection between the undamaged portions of an underwater pipeline are universal. First of all, any apparatus which is positioned between the undamaged ends of the pipeline must be able to connect to such undamaged ends in spite of the undamaged portion of the pipe being of a slightly unpredictable diameter due to manufacturing tolerances. The undamaged portions of the pipeline may also be corroded or out of round. All of these factors contribute to make actual pipeline conditions for insertion of a coupling device between undamaged portions of a pipeline unpredictable. Further difficulties are encountered due to the fact that such pipelines are being laid at greater and greater depths; for the greater the depths of the pipeline, the more difficult are the working conditions for the divers accurately installing a coupling device for connecting together the undamaged portions of the pipeline.